Precombustion chamber



April 12, 1960 J. E. wlTzKY 2,932,289

PRECOMBUSTION CHAMBER Filed Oct. 20. 1958 United States Patent iPRECGMBUSTION CHAMBER Julius E. Witzky, Cleveland Heights, OhioApplication October 20, 1958, Serial No. 768,095 7 Claims. (Cl. 12S-32)T his'invention relates broadly to diesel engines, and

more specifically to engines of the type that embody a combustionchamber is vellipsoidal with the Vmajor axisl thereof normal tothemedialaxis of the precombustion chamber outlet. When the pistonapproaches'top dead center positionin the compression stroke, the airadmitted through the intake valve and displaced from the cylinder willbe forced into the main combustion chamber in a divided swirlingmovement, and when combustion in the precombustion chamber is initiated,a. fuelame mixture with high velocity will be forced through the throatof the chamber into the swirling air of the main combustion chamber.

, The capacity of the precombustion chamber is approximatelytwenty-eight (28) to thirty-two (32) percent of the compression volume,and the capacity of the combustion chamber is forty `(40) to forty-five(45) percent of the compression volume.

The primary object of the invention is to provide a combustion chamberwith a sharp edge or rim around the 'opening thereto and curved side andend walls so the fuel mixture will follow the contour thereof at a highrate of velocity, and thus effect a controlled swirling ymovementof thefuel charge in each end ofthe ellipsoidal cavity. Such movement of theair will effectuate af thorough and complete admixture of the fueltherewith" and the consequent high utilization of air at a high mean'Veffective pressure.

A further object of the invention is to provide a passageway or throatbetween the combustion chamber and precombustion conduit of liberalproportions in order to reduce ,the pumping losses and lower` the fuelconsumption. I i

Another object of the invention is to provide a passageway or throat inthe combustion chamber of suicient size to facilitate the readyadmission of air without appreciable thermal loss so the fuel injectedtherein may be readily ignited during initial combustion and startingdiiiiculties eliminated.

Other objects and advantages more or less ancillary to the foregoing,and the manner in which all the various objects are realized, willappear in the following description, which considered in connection withthe accompanying drawings, sets forth the preferred embodiment of theinvention.

Referring to the drawings:

Fig. 1 is a vertical sectional view of the upper portion of an engineassembly embodying the invention.

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`VReferring to Fig. 1,v the enginecomprises a cylinder block "having` abore 11 therein for a cylinder liner 12. A piston 13 is mounted in aconventional manner in the bore 14 of the liner, the head 1S of thepiston being'formed with a recess therein Ydefining an ellipsoidal Ycombustion chamber 17. The throat 18 of the 'combustion chamber iseccentric the medial axis of the piston, and the inner edges 19thereofoverhang the cavity that defines the ellipsoidal chamber in order toeiect a swirling motion of theY air (indicated in the combustionchamber,17,by.dotted,lines) delivered through a valve port 20 which iscontrolled by an air inlet valve 21. p

VThe top ofthe cylinder is provided with a cylinder head'ZZ, which likethe cylinder block, is formed with arwaterr-jacket 23 for thecirculation of a coolant.

the head Yby a* sleeve 26 having a hemispherical end porf tion thatcompletesthe spheroidal precombustion chamber 25. The sleeve 26 is heldin place by a collar 27 threadedV into thecylinder head. The insert 24may be made Afrom a material of low thermal heat conductivity, but ofhigh heat resistance. defineV the spheroidal precombustion chamber 25,and

the Ylower end thereof has a tubular conduit 23 protrudi ing therefromwhich terminates adjacent the lower face of the cylinder head. Thetubular conduit 28 deiines outlet canal 29 'for the discharge of theignited fuel and thefunburnt products of combustion. The opposed end ofthe precombustion chamber 2S is retained by the sleeve 216, theboretherein being drilled and` tapped for the reception ofy a fuel injectionnozzle 30 communica#A ing with the chamber 25. The cylinder head and`the insert 24 may, if desired, be cross-drilled for the reception of vaglow plug 31 having the incandescent end thereof in the chamber 25.

In a Vwater cooled engine, the intake and exhaust valves are inclinedrelative to the medial` axis of the cylv inder to facilitate'thedisposition of the precombustion chamber and injector relatively closeto the vertical center lineV of the cylinder. In addition, the inclinedvalve' arrangement affords the advantage of a cylinder' head with adome-shaped rcontour which increases the stiffness and rigidity of thestructure.

`The openingin the conduit 28 and the throat 1S of. th'elcombustionchamber are disposed in aligned relation l' Hence, when the llame andunburnt vproducts of. combustion from the precombustion chamber enterthe main combustion chamber, a'thorou'gh mixture` of air.

and theunburnt particles of fuel will producea highly combustiblegas'dueto the controlled swirling movementl ofthe air in the maincombustion chamber.

Ani-"engine of the present invention may be readily startedsince some'of thev fuel injected into the main combustion chamber 17 during thestarting period willf' penetrate thecirculating air` inthe main.`Vcombustion-'` chamber where the temperature of the compressed air ishigh enough to initiate ready ignition.

Although the foregoing description is necessarily of a detailedcharacter, in order that the invention may be completely setV forth, itis to be understood that the specific terminology is not intended to berestrictive or confining, and that various rearrangements of parts andmodifications of detail may be resorted to without departing from thescope or spirit of the invention as herein claimed.

What is claimed is:

l. A diesel engine comprising a cylinder block having a cylindertherein, a piston in said cylinder having an ellipsoidal combustionchamber in the head thereof, a cylinder head on said block having arecess therein, a

Patented Apr. 12., .1960.

The cylinder head has a hollow insert 24 therein constitut-v Ving aprecombustion chamber 25 which is retained in The walls, of the insert24r 3 precombustion chamber insert in said recess, Vsaid insertcomprising a spheroidal bowl, a ange on the top thereof, a sleeveengagedwith said flange, `a threaded collar in the cylinder block engaged withsaid Lsleevelcfor Vthe retention thereof, a fuel nozzle threaded in *thetopdof said sleeve communicating with said spheroidal precombustionchamber, a diametrically.restricted'ledge circumambient the top of saidcombustion chamber to effect a swirling movement of air in saidcombustion chamber, the llame and fuel from said precombustion chamberpenetrating the swirling` air in said combustion chamber when the pistonreaches the top of its lcompression stroke. s Y

2. A diesel engine comprisinga cylinder Abloclchaying a cylindertherein, a piston in saidcylinder having an ellipsoidal combustionchamber in the head thereof,

a cylinder head on said block having a recess thereirnal precombustionchamber insert in s aid recess, said insert comprising a spheroidalbowl, a flange on the top thereof, a sleeve engaged with said ange, athreaded collar in the cylinder block engaged with said sleeve for theretention thereof, 1a fuel nozzle threaded inhthe top of said sleevecommunicating with said spheroidal pr ecombus tion chamber, a glow plugin said precombustion chamber, a diametrically restrictedledge/circumambient the top of said combustion chamber to effect aswirling movement of air in said combustion chamber, the llame and fuelfrom said precombustion chamber penetrating the swirling air in saidcombustion chamber when the piston Vreaches the top of itscompressioncstroke. Y y

3. A`n internal combustion engine comprising Va `cylinf der block, acylinder therein, a piston in saidvcylinder having an ellipsoidalcombustion chamberdin the Vhead thereof, a cylinder head on said blockhaving arsphlef roidal precombustion chamber therein, a tubular conduitin said head' having an outlet canal therein communieating with thecenter of said combustion chamber in' said piston, ya fuel nozzle insaid head communicating with said precombustion chamber, said pistonhaving an opening in the head thereof forrthe entry of the end portionof said conduit, said opening being approximately five times thediameter of said outlet canal in said conduit, a ledge circumambientsaid opening, the wall of said combustion chamber subjacent said ledgeundercut to -dene a sharp edge with the walls thereof curved to dellectthe air in said chamber over the walls of said combustion chamber andeffect swirlingrmovement of the air in said combustion chamber, the fuelfrom precombustion chamber penetrating the swirling air in saidcombustion chamber and delivering `it when the fuel is injected therein.c

4. An internal combustion engine comprising a cylinder block havingpassageways therein'for the circulation ber, a tubular outlet conduit inthe center of saidlcylinder head normal to the horizontal axis, a fuelinjection nozzle in said precombustion chamber, a ledge overhanging saidcombustion chamber and having a sharp edge and an opening therein, thedimension of the maximum diameter thereof being greater than the openingin the combustion chamber, whereby fuel from the precombustion chamberpenetrates the vertical axis of the swirling air in said combustionchamber when injected therein.

5. An internal combustion engine comprising a cylinder block, a cylindertherein, a piston in said cylinder having an ellipsoidal combustionchamber in the head thereof, a cylinder head on saidY block having aspheroidal precombustion chamber therein, a tubular outlet conduit inthe center of said precombustion chamber communicating with the centerof said combustion chamber, Ia fuel nozzle in said head communicatingwith said precombustion chamber, a ledge circumambient the top of saidcombustion chamber, the wall of said combustion chamberbeing curvedoutwardly and of .dimensions tion chamber and divide it into twoswirling paths.

6. A diesel engine comprising a cylinder block having a cylindertherein, a piston in said cylinder having an Iellipsoidal cavity in thehead thereof constituting `a combustion chamber, a cylinder head on saidblock having a spheroidal cavity thereinV constituting a precombustionchamber, a conduit in'the center of said precombustion chamber alignedwith the vertical axis of said combustion chamber, a fuel injectionnozzle'in said precombustion chamber, a ledge circumambient the throatof said combustion chamber, the wall of said combustion chamber beingarcuate, whereby the ame and unburnt fuel from said precombustionchamber will divide the air in the combustion chamber and produce aright and a left hand swirling mixture. ,v

Y7. A diesel engine comprising a lcylinder block, a cylinder therein, apiston in said cylinder having an ellipsoidal combustion chamber in thehead thereof having an opening in the center thereof, a cylinder head onsaid block having a spheroidal precombustion cham'- ber therein, atubular conduit from said precombustion chamber protruding through theopening in said combustion chamber, a fuel nozzle in said precombustionchamber, a sharp ledge surrounding the opening in said combustionchamber, said ledge being smaller than the maximum diameter of saidcombustion chamber, whereby unburnt fuel from said precombustion chamberwill enter the center of said combustion chamber and penetrate the airtherein at the top dead center of stroke of said piston.

' 'Great Britain oct 2o, 1954 Switzerland May 15, 1957

